This invention relates to a piezoelectric motor employing electrostrictive vibration of piezoelectric (electrostrictive) elements, and more particularly to a piezoelectric motor using multilayer piezoelectric elements.
A piezoelectric motor uses for its drive the electrostrictive strain induced when a voltage is applied on a piezoelectric element. Since a piezoelectric motor does not need a coil required in the conventional electric motor, the piezoelectric motor is simpler in structure and reduced in size compared to a conventional motor. The piezoelectric motor is further advantageous in that low speed rotation is achievable in a large torque without the use of reduction means such as gears. An example of such a piezoelectric motor is described in U.S. Pat. No. 4,495,432 in which piezoelectric elements generate traveling waves to rotate a rotor. However, the piezoelectric motor of U.S. Pat. No. '432 has the disadvantage that it needs a high driving voltage since it uses piezoelectric elements utilizing transverse electrostrictive effect.